Why is it a rat's nest immediately after washing??

So I have pretty long, fine,stick straight hair. I get it cut and colored literally once a year. Other than that it's usually just up in a bun. A few years ago I moved to a place that has hard water and put a filter on my showerhead to try to avoid the hard water. After shampooing (I recently switched to Head and Shoulders because my scalp has been so dry. I've never had dandruff until I moved to California but my hair is revolting). I condition with either Tresemme, Aussie 3 minute miracle or a conditioning mask. Once I'm out of the shower I use a Garnier leave in conditioner. After all that, this is what I get. The finest little tangles and snarls and it takes me a good half hour to brush out. What is going on here and how do I make it better?